Turntable with short radius roller ring



Jan. 7, 1969 0. B. JOHNSON ETAL 3,420,187

TURNTABLE WITH SHORT RADIUS ROLLER RING Filed March 28, 1967 ATTORNEYS.,

United States Patent 11 Claims ABSTRACT OF THE DISCLOSURE This inventionrelates to turntables of a type that are used in automobile showrooms,railroad stations and at other locations for advertising displays ofautomobiles or other items. More particularly, the invention relates toturntables that have a short-radius circle for the supporting rollersand that have the turntable beyond the roller circle of cantileverconstruction. a

It is an object of the invention to provide an improved construction forturntables that have small roller circles. While turntables having largeroller circles usually have only about of the radius of the turntablebeyond the supporting rollers, a turntable with a small roller circlehas most of its radius beyond the supporting rollers. It will beunderstood that large and small, as used herein, have nothing to do withdimensions, but with proportions. For purposes of the description ofthis invention, the expression small roller circle means a roller circlehaving a diameter less than half of the diameter of the turntable andthese small roller circles involve problems different from those ofturntables having larger roller circles.

A turntable having a large roller circle has supports at three or fourlocations across the diameter of the turntable, whereas the smallerroller circle turntable has supports at only two locations, though thediameter of the turntable may be just as large in one case as the other.These differences will be explained in connection with the drawing.

All else equal, the loading of the individual rollers of a small rollercircle turntable is substantially higher; partly because there are fewersupports across the diameter of the turntable, but also because thereare fewer rollers to take the load in a smaller circle than in a largeone. Therefore, the presure of each roller against the bottom of theturntable is greater.

Because of this greater pressure, more wear is to be expected, andactually the wear is greatly increased because of the reducedcircumference of the surface of the turntable that contacts with therollers; that is, the wear is concentrated in a shorter length ofarcuate surface of the turntable.

There is another factor, however, that tends to produce an even greatereffect in the wear, and this is the alignment. The supporting rollersfor a turntable are tapered and have their axes of rotation inclined sothat the apex of the conical surface is on the axis of rotation of theturntable and at the level of the plane of the bottom surface of theturntable that contacts with the rollers. Precise alignment is difficultto obtain, and because of the reduced spacing of the rollers from theaxis of rotation of the turntable the same actual dimensionalmisalignment is proportionately greater in a small circle than in alarge one because it is a larger percentage of the angle.

It is another object of this invention to provide a small roller circleturntable with rollers supported with sloping axes in alignment bothhorizontally and vertically with the same point on the axis of rotationof the turntable,

and to provide an improved construction for replacing worn or defectiverollers without disturbing the alignment of the roller supports andWithout requiring any realignment for a new roller.

This invention reduces the cost of production of turntables of thecharacter indicated, reduces wear, facilitates the replacement ofrollers, and reduces maintenance expense.

Other objects, features and advantages of the invention will appear orbe pointed out as the description proceeds.

In the drawing, forming a part hereof, in which like referencecharacters indicate corresponding parts in all the views:

FIGURE 1 is a diagrammatic view showing the construction of a turntablehaving a large roller circle;

FIGURE 2 is a diagrammatic view, similar to FIG- URE l, but showing aturntable having a small roller circle;

FIGURE 3 is an isometric view showing a turntable made in accordancewith this invention and showing the way in which an automobile islocated on the turntable;

FIGURE 4 is an exploded view of the turntable shown in FIGURE 3, theparts being turned to different positions;

FIGURE 5 is a greatly enlarged, fragmentary, sectional view of a portionof the turntable and one of the supporting brackets shown in FIGURE 4;and

FIGURE 6 is a side elevation of the roller support shown in FIGURE 5.

FIGURE 1 shows a turntable 10 supported at the center by a post 12 andsupported at angularly spaced locations near its periphery by rollers14. This turntable has three supports and the rollers 14 are locatedaround a roller circle which is at a distance from the center equal toof the radius of the turntable. The peripheral portion of the turntablebeyond the circle of rollers 14 has cantilever support that ispreferably not over 20% of the radial extent of the turntable.

Often the turntable is supported by another circle of rollers, similarto the rollers 14 but located much closer to the center of rotation andthese inner rollers may take the place of the support provided by thepost .12 in FIG- URE 1. If they do, then the turntable is supported atfour locations across its diameter instead of at three, as in FIGURE 1.

FIGURE 2 shows a turntable 20 which has a center post 22 and supportingrollers 24. The supporting rollers 24 are located at angularly spacedregions around a roller circle which has a radius very much smaller thanthat of the turntable 20. In the construction illustrated, the radius ofthe roller circle for the rollers 24 is only 30% of the radius of theturntable 20, and thus 70% of the turntable 20 is a cantileverconstruction. With the rollers 24 located close to the center ofrotation, it is not necessary to have the post 22 support the turntable,and in the construction shown the post 22 merely holds the turntableagainst transverse movement without providing any support.

FIGURE 3 shows the turntable 20 which includes a hub portion 28 witharms 31 and 32 extending from opposite sides of the hub portion 28 andfor substantial distances beyond the hub portion. There is a front crossarm 33 connected with the outer end portion of the arm 32 and there is acorresponding rear cross arm 34 connected near the rearward end of thearm 31.

These cross arms 33 and 34 hold small platforms 36 on which the wheelsof an automobile can be located. FIGURE 3 shows an automobile inphantom, and this automobile is designated by the reference character40.

The turntable 20 can be designed for a particular make and model ofautomobile and in such case, is not adjustable in size; but the arms 31and 32 are preferably made of telescoping sections so that they can belengthened or shortened to accommodate automobiles of differentwheelbase. The cross arms 33 and 34 can also be made of telescopingsections to accommodate automobiles of different tread, but theprovision of this adjustment is less important than the lengthadjustment because most automobiles have a standard tread.

It will be apparent that a turntable of the type shown in FIGURE 3 withthe load carried on platforms on arms which extend from a center hubportion, must necessarily have a small roller circle because there is nocircumferential continuity to any of the turntable beyond the hubportion 25.

FIGURE 4 is an exploded view showing the telescoping arms 31 with theirsections separated to illustrate the construction. Each of the arms 31and 32 has an outer section 42 which is rigidly connected to the crossarms 33 and 34, respectively. Each arm 34 also has a section 44 which isrigidly connected with the hub portion 28 and these sections 44telescope into the sections 42 and can be held in any adjusted positionby pins 46 extending through an opening 48 in the outer section 46 andany one of a number of openings 50 spaced along the length of the innersection 44. Thus the turntable can be conveniently disassembled forshipment.

The turntable 20 has a base 54 which forms the bottom of the hub portion28. This base 54 can be attached to the fioor, if desired, and must beattached to the floor if the load is to be unbalanced with respect tothe axis of rotation by any substantial amount. For balanced loading orloading which is only slightly unbalanced and which leaves the center ofgravity still within the confines of the base 54, it is not necessary toattach the base to the floor on which the turntable is supported.

The base 54 is increased in rigidity by ridges 56 which are preferablyan integral part of the base. The base has a center post 22 supported ina bearing 58 attached rigidly to the base 54. The upper end of the post22 can be fastened to the turntable 20 but this is not essential. In theconstruction illustrated, the post 22 is secured to the turntable 20 asan integral part of the turntable and extends into the bearing 58 toprevent lateral displacement of the turntable, but the post 22 andbearing 58 preferably carry none of the weight of the turntable.

Roller brackets 60 are attached to the ridges 56 in the constructionillustrated. They may be attached to other parts of the base 54 but theadvantage of using the ridges is to distribute the load over a greaterarea of the base 54.

On top of each of the brackets 60, there is a horn 64 secured to thebracket by bolts 66. An axle 68 extends through opposite sides of thehorn 64 and supports a roller 70. There are two rollers 70- in theillustrated construction and a third roller 70 which is of the sameconstruction as the rollers 70 except that it is wider and provided witha belt groove 72 by which the roller 70' is driven from a motor 74secured to the base 54.

The motor 74 has a belt 76 which passes around pulleys to drive a speedreducer unit 76. The low-speed end of the speed reducer unit 76 isconnected by a belt 78 to the roller 7 the belt 78 running in the groove72 of the roller. The speed reducer unit 76 is attached to anglesupports 80 by bolts extending through slots in the angles so that thespeed reducer unit can be shifted to change the tension in the belts.The motor 74 is similarly connected to the base 54 by bolts extendingthrough slots to permit further adjustment of the belt tension.

FIGURE shows the roller 70' on an enlarged scale. The axle 68 supportsthe inner part of a ball bearing and the outer part fits snugly in theroller 70. Rollers can be replaced by sliding the axle 68 out of theball bearing and then removing the roller from the born 64. A new rolleris placed in position in the horn and the axle 68 is pushed through thebearing of the new roller and secured in position by nuts 86 on the endsof the shaft.

The bracket 60 slopes so that the axle 68 which is substantiallyparallel to the top of the bracket 60, extends along a line 88 which isthe axis of the conical or tapered circumferential surface of the roller70'. The apex of this tapered surface is at a point 90 which is on theaxis of rotation of the turntable, which axis is designated by thereference character -92. The point 90 is also located in the plane of abottom surface 94 that contacts with the roller 70' to support theturntable. This construction provides minimum friction and wear.

When the turntable is originally assembled, shims can be placed betweenthe horn 64 and the bracket 60, if necessary, in order to align the axis88 with the point 90. It will be apparent, however, that by having theaxle 68 removable, to replace rollers, without moving the born 64, makesthe original alignment permanent and there is no necessity forrealignment when worn rollers are changed. The rollers 70 and 70' arepreferably made of plastic and with their brackets are rigid casterrollers.

Although this invention is particularly useful with turntables havingsmall hubs and supporting arms which have little circumferential extent,circular platforms can also be placed on the turntable where the itemsto be displayed can be displayed more effectively on a continuous roundturntable. The construction therefore has greater flexibility in theuses to which it can be put than in the case of turntables having largeroller circles and which, therefore, require continuous circumferentialextent of the turntable at distances close to the outer limits of theturntable.

What is claimed is:

1. In a turntable, a base, a rotatable top for carrying a load that isto be displayed, bearing means for preventing displacement of the top ina radial direction from its axis of rotation, rollers under therotatable top and at angularly spaced locations around a circle forsupporting the rotatable top, bracket means connecting each of therollers with the base and supporting the rollers from the base, thebracket means having an axle for each of the rollers, each axleextending radially from the axis of rotation but at an acute anglethereto in a vertical plane, the bracket means being fixed to the baseand the axle of each roller being removable from the bracket means forremoval and replacement of the roller, a circular surface under therotatable top for contact with said rollers as the top rotates, thediameter of the roller circle being less than one half the radius of thearea swept by said rotatable top, and each of the rollers having atapered face forming a portion of the area of a cone with its apexsubstantially on the axis of rotation of the top, and the axis of eachaxle being in line with the intersection of the axis of [rotation of thetop and the plane of the circular surface that contacts with saidrollers on which the top rotates.

2. The turntable described in claim 1 characterized by the bracket meanscomprising a separate horn for each roller with upstanding portions ofeach horn extending up on opposite sides of the roller and the axleextending through a bearing in the roller and being supported onopposite sides of the roller by said upstanding portions of the born.

3. The turntable described in claim 2 characterized by the base having asloping surface on which each horn is supported, the sloping surfacehaving the same slope as each axle and each horn supporting its axle atthe same distance above the base on both sides of the roller.

4. The turntable described in claim 1 characterized by the rotating tophaving a hub portion of continuous circumferential extent and havingarms extending beyond the hub portion at diametrically oppositelocations on said hub portion, and load-carrying elements connected tothe arms.

5. The turntable described in claim 4 characterized by the load-carryingelements being platforms located in position to support the wheels of anautomobile, and

at least one of the arms being adjustable to accommodate the turntableto automobiles of different wheelbase.

6. The turntable described in claim 5 characterized by the arms havingcross arms at their ends remote from the hub portion, the mid region ofeach cross arm being connected to one of the other arms, and theplatforms being connected to opposite ends of the cross arms.

7. The turntable described in claim 6 characterized by the adjustablearm comprising two sections, one of which telescopes into the other, oneof the sections being secured to the hub portion, and the other of thesections being secured to one of the cross arms.

8. The turntable described in claim 7 characterized by both of the armswhich extend from the hub portion to the cross arms being adjustable inlength so that the spacing of the cross arms from the supporting rollerscan be adjusted to maintain the center of gravity of a supported load ata location within the roller circle.

9. The turntable described in claim 8 characterized by power drivingmeans including a belt for transmitting motion to one of the rollers,and one of said rollers under the rotatable top having a circumferentialgroove therein into which the belt fits for driving said roller.

10. The turntable described in claim 9 characterized by the powerdriving means being located within the base and including an electricmotor, a speed reducer driven by the electric motor, a pulley at thelow-speed end of the speed reducer, the belt which drives said rollerbeing located in position to run on the speed reducer pulley and on theroller having the belt groove for transmitting power from the speedreducer directly to said roller having the belt groove.

11. The turntable described in claim 1 characterized by the rollersbeing made of plastic and having antifriction bearings therein supportedby the axles that are removable from said brackets for removal andreplacement of the rollers.

References Cited UNITED STATES PATENTS 3/1962 OToole 104-44 2/1968OToole 104-44 US. Cl. X.R.

